Benchmark: concat vs spread 2

Tests:

concat
const arr1 = new Array(500).fill(null).map(() => Math.random()); const arr2 = new Array(300).fill(null).map(() => Math.random()); const arr3 = arr1.concat(arr2);
spread
const arr1 = new Array(500).fill(null).map(() => Math.random()); const arr2 = new Array(300).fill(null).map(() => Math.random()); const arr3 = [...arr1, ...arr2]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat
spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.110 Safari/537.36

Browser/OS: Chrome 96 on Windows

View result in a separate tab

Test name	Executions per second
concat	6599.3 Ops/sec
spread	5405.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared, and some of the considerations.

**Benchmark Definition**

The provided JSON represents a benchmark definition for measuring JavaScript performance. It defines two test cases:

1. "concat": Tests the concatenation of two arrays using the `Array.prototype.concat()` method.
2. "spread": Tests the spread operator (`...`) used to concatenate two arrays.

**Options Compared**

In this benchmark, we have two options compared:

* `Array.prototype.concat()`: The traditional way of concatenating arrays in JavaScript.
* Spread operator (`...`): A newer syntax introduced in ECMAScript 2015 (ES6) that allows for more concise and expressive array concatenation.

**Pros and Cons**

Here are some pros and cons of each approach:

* `Array.prototype.concat()`: Pros:
	+ Widely supported across different browsers and versions.
	+ Easy to understand and implement.
* Cons:
	+ Can be slower due to the overhead of creating a new array and copying elements.
	+ Not as concise or expressive as the spread operator.
* Spread operator (`...`): Pros:
	+ More concise and expressive than `concat()`.
	+ Can lead to faster performance since it avoids the creation of a new array.
* Cons:
	+ Not supported in older browsers (pre-ES6).
	+ May not be as intuitive for developers unfamiliar with this syntax.

**Library Used**

In both test cases, no external libraries are used. The `Array.prototype.concat()` method and the spread operator (`...`) are built-in JavaScript features.

**Special JS Feature/Syntax**

The use of the spread operator (`...`) is a feature introduced in ECMAScript 2015 (ES6). It allows for more concise array concatenation, but it's not supported in older browsers. This means that if you want to ensure compatibility across different browsers, using `concat()` might be a safer choice.

**Other Alternatives**

If you need to compare other array concatenation methods or syntaxes, you can consider adding additional test cases. Some alternatives could include:

* Using `Array.prototype.push()` and `push()`: This method modifies the original array by appending new elements.
* Using `concat()` with a callback function: This approach can be useful when working with asynchronous data or when performance is critical.

For example, you could add another test case to compare `push()`:
```json
{
  "Benchmark Definition": "const arr1 = new Array(500).fill(null);\r\nconst arr2 = new Array(300).fill(null);\r\narr1.push(...arr2);",
  "Test Name": "push"
}
```
This test case would measure the performance of using `push()` to concatenate two arrays.

Related benchmarks:

concat vs spread 2 (version: 0)

Comparing performance of: concat vs spread

Created: 3 years ago by: Guest

Jump to the latest result

concat

spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):